The proposed project will investigate neural correlates of perceptual expertise for faces and letters in autism spectrum disorder (ASD). Abnormal attention to faces is one of the earliest developmental symptoms of ASD, and, throughout the lifespan, individuals with ASD tend to exhibit problems with face recognition along with atypical visual scanning patterns for faces and abnormal hemodynamic brain activity during face perception. The social motivation hypothesis, a theory of face processing impairments in ASD, suggests that these deficits reflect a lack of expertise resulting from poor social motivation and limited interest in and attention to people during development. The current study will use behavioral assessments and event-related potentials (ERPs) to examine behavioral and neural correlates of expertise for faces and letters in 25 10 to 16 year-old children with ASD and 25 typical peers matched on age, sex, cognitive ability, and handedness. It is hypothesized that, in keeping with the predictions of the social motivation hypothesis, individuals with ASD will show atypical specialization for faces but intact specialization for non-face expert stimuli (letters). The first goal of this study will be to elucidate patterns of electrophysiological brain activity during face perception in individuals with ASD. It is predicted that individuals with ASD will exhibit delayed and attenuated face-related ERP responses and that these responses will correlate with behavioral measures of face recognition and perception. This study will be the first to localize neural generators for ERP components associated with face processing in a large sample of children with ASD. By combining data from collaborative eye-tracking and neuroimaging studies of face perception, this study will explore interrelationships among electrophysiological brain activity, visual attention, and hemodynamic brain activity during face processing. A second goal of this study will be to reveal normative behavioral and brain specialization for letters, thus demonstrating intact capacity for development of non-face perceptual expertise. Results of the current study have significant implications for understanding the pathophysiology of ASD, describing developmental bio-behavioral markers of ASD, and defining quantifiable traits for genetic analyses. Findings may also inform development of interventions for children with ASD. By examining neural activity to letters in older children with ASD, this study will also lay groundwork for future research into the early development of perceptual expertise in very young children with ASD who display strong interest and precocious decoding ability for letters and words in early childhood. 7. Project Narrative: This study will elucidate patterns of electrical brain activity during face and letter perception in children with autism spectrum disorder (ASD), including its sources within the brain and its relationship to behavioral performance. These results will be important in terms of clarifying the nature of brain dysfunction in ASD, developing interventions, describing quantifiable traits for genetic analyses, and specifying brain-based markers of early atypical social development. [unreadable] [unreadable] [unreadable]